Cutting mechanism

ABSTRACT

A cutting mechanism for cutting photographic sheet material from a roll in photographic reproduction equipment. The cutting mechanism consists of a first fixed blade and a second movable blade. The second movable blade is supported for a lateral cutting movement relative to the first fixed blade by a pair of parallel strip springs which are mounted in a cantilever manner to a frame. The strip springs are flexed laterally by a drive mechanism which results in the second blade moving laterally relative to the first blade with a constant angle between the cutting edges of the first and second blades. The second blade is biased against the first blade by a third strip spring at one end and a roller at the other end.

Fairbanks June 12, 1973 CUTTING MECHANISM [75] Inventor: Henry N. Fairbanks, Rochester,

[73] Assignee: Itek Corporation, Lexington, Mass.

[22] Filed: Sept. 23, 1971 [21] Appl. No.: 182,992

[52] US. Cl. 83/589, 83/602, 83/628,

83/636, 83/642, 83/694 [51] Int. Cl 826d 5/16 [58] Field of Search 83/588, 642, 589,

[56] References Cited UNITED STATES PATENTS 3,453,919 7/1969 Ehrat et al. 83/589 3,151,515 10/1964 Juverkrop 83/588 X 388,343 8/1888 Curtis 83/589 X 2,186,884 1/1940 Shomaker 83/589 X 3,234,840 2/1966 Smeets 83/589 UX 613,322 11/1898 Schuermann ..83/588X Primary Examiner-Frank T. Yost Attorney-Homer 0. Blair, Robert L. Nathans and William C. Roch [57] ABSTRACT A cutting mechanism for cutting photographic sheet material from a roll in photographic reproduction equipment. The cutting mechanism consists of a first fixed blade and a second movable blade. The second movable blade is supported for a lateral cutting movement relative to the first fixed blade by a pair of parallel strip springs which are mounted in a cantilever manner to a frame. The strip springs are flexed laterally by a drive mechanism which results in the second blade moving laterally relative to the first blade with a constant angle between the cutting edges of the first and second blades. The second blade is biased against the first blade by a third strip spring at one end and a roller at the other end.

9 Claims, 1 Drawing Figure 1 CUTTING MECHANISM BACKGROUND OF THE INVENTION The present invention relates generally to a cutting mechanism, and more particularly pertains to a new and improved cutting mechanism for cutting sheet material.

Cutting mechanisms have been designed for use in photographic reproduction equipment wherein lengths of photosensitive material are desired to be severed from a roll of such material. A cutting mechanism designed for this purpose must be relatively compact to fit within the machine, and must be very reliable over a great number of cutting operations. One approach taken by the prior art is to use a power driven scissor mechanism in which the scissor blades are curved to maintain the cutting angle between the two blades constant as the scissor mechanism is closed. This approach has the disadvantages of taking up a good deal of space within the machine and also requiring curved cutting blades. Another approach of the prior art has been to drive a movable blade relative to a fixed blade by a rack and pinion drive mechanism. A problem with this arrangement is that the cutting mechanism must be continually finely adjusted to maintain the cutting angle between the cutting blades constant at a desired cutting angle, and also the rack and pinion drive mechanism requires an expensive reversing motor. Still another approach involves the driving of a movable blade relative to a stationary blade with a linkage mechanism. This approach is illustrated in U. S. Pat. No. 3,376,775. This approach results in a relatively cumbersome and complex cutting mechanism.

SUMMARY OF THE INVENTION In accordance with a preferred embodiment, a cutting mechanism is disclosed wherein a movable cutting blade is supported for movement relative to another cutting blade by a pair of parallel strip springs which are mounted in a cantilever manner to a frame. The support action of the strip springs is such that the cutting angle between the movable blade and the other blade is maintained constant. Further, the preferred embodiment provides a cutting mechanism which may be simply constructed and which does not require continual adjustment. Still.further, the preferred embodiment provides a cutting mechanism which may be driven by a simple motor or solenoid. Also, the preferred embodiment provides a cutting mechanism wherein the two cutting edges may be straight edges, thus eliminating the expense of curved cutting edges.

BRIEF DESCRIPTION OF THE DRAWING Referring to the FIGURE there is illustrated a cutting mechanism for a roll of sheet material in a photographic reproduction machine.

DESCRIPTION OF A PREFERRED EMBODIMENT The cutting angle between two cutting blades may vary between zero and ninety degress. An optimum cutting angle may be selected by a trade off of two parameters. The first parameter is compactness of the cutting mechanism. The cutting mechanism will require the least space if the cutting angle is near and will require the most space as the cutting angle approaches 90. Based on this parameter a cutting angle near 0 would be desirable. The second parameter to be considered is the power required to drive the cutting mechanism. The greatest amount of power will be required as the cutting angle approaches zero degrees. For this reason a cutting angle greater than zero degrees is desirable. Based on the above considerations a cutting angle slightly greater than zero degrees would be desirable, but the cutting mechanism must be designed such that the cutting angle does not vary toward zero degrees. Otherwise, the power source designed to drive the cutting mechanism might be insufficient, thereby causing a breakdown of the mechanism. A preferred cutting angle for two cutting blades would be in the range of from three to five degress. A cutting mechanism operating in this range must be designed so the cutting angle between the blades does not vary, and particularly does not approach zero degrees. The preferred embodiment of the invention was designed with the above considerations in mind.

The cutting mechanism has first and second blades 12 and 14. The first blade 12 is fixedly mounted to the machine frame 15. The second blade 14 is movably mounted in the machine by a pair of parallel strip springs 16 and 18. Strip springs 16 and 18 are maintained parallel by brackets 20 and 22 at first and second ends. Bracket 20 mounts the first ends of the strip springs to the machine frame 15 such that the springs are supported in a cantilever manner. In the cantilever support arrangement the second ends of strip springs 16 and 18 and bracket 22 move freely in a lateral direction along arrow 19. This lateral movement flexes each of the strip springs, and produces compression on one side of each strip spring and tension on the other side. The support arrangement of the strip springs resists angular movements of bracket 22 about three axes and lateral movements of the bracket along two axes. Also, the support arrangement restrains bracket 22 against angular rotations during lateral movement of the bracket, and allows bracket 22 to laterally drive movable blade 14 relative to fixed blade 2 while maintaining the cutting angle between the blades constant. A preferred cutting angle for the blades would be in the range of from three to five degress. A third strip spring 24 mounts the blade 14 to bracket 22, and provides a downward force on blade 14 to maintain the cutting edges of the two blades in constant contact. A roller 26 is also provided for the same purpose. In an alternative embodiment blade 14 might be bowed downwardly against blade 12 to assist in maintaining the cutting edges of the two blades in constant contact, and roller 26 might be eliminated. The second blade 14 is driven laterally relative to the first blade 12 by a prime mover means 28 which may be a simple rotary motor. Motor 28 rotates crank member 30 which in turn actuates drive member 32. Drive member 32 is pivotally connected to bracket 22. In an alternative embodiment the spring action of strip springs 16 and 18 might be utilized to provide the cutting force, and motor 28 would be used to cock the springs.

While several embodiments have been described, the teachings of this invention will suggest many other embodiments to those skilled in the art.

I claim:

1. A cutting mechanism comprising:

a. a frame member;

b. a first blade mounted to said frame member;

0. a second blade; and

0nd ends together to allow a lateral flexing movement of said second ends while preventing twisting movements thereof, and means for mounting said second blade to said securing means to position said second blade such that its length extends in substantially the same direction as the lengths of said pair of strip springs and to provide for a cutting movement of said second blade relative to said first blade during said lateral flexing movement while said first and second blades are maintained at said predetermined cutting angle due to the prevention of twisting movements of said second ends.

2. Apparatus as set forth in claim 1 wherein said means for mounting said first ends to said frame member include means for mounting said first ends a predetermined distance apart, and said securing means includes means for securing said second ends together at said predetermined distance apart, whereby said springs are parallel to each other.

3. Apparatus as set forth in claim 2 wherein said meansfor mounting said second blade to said securing means includes a third spring for pressing said first and second blades together.

4. Apparatus as set forth in claim 3 wherein said third spring includes a third strip spring.

5. Apparatus as set forth in claim 4 wherein:

a. said second blade has first and second ends;

b. roller means are provided adjacent to said first end of said second blade for pressing said second blade against said first blade; and

c. said means for mounting said second blade to said securing means includes means for fastening'said third strip spring adjacent to said second end of said second blade.

6. Apparatus as set forth in claim 5 and further including a prime mover means for laterally moving said securing means, whereby the cutting mechanism is actuated.

7. Apparatus as set forth in claim 1 wherein said means for mounting said second blade to said securing means includes a third spring for pressing said first and second blades together.

8. Apparatus as set forth in claim 7 wherein said third spring includes a third strip spring.

9. Apparatus as set forth in claim 8 wherein:

a. said second blade has first and second ends;

b. roller means are provided adjacent to said first end of said second blade for pressing said second blade against said first blade; and

c. said means for mounting said second blade to said securing means includes means for fastening said third strip spring adjacent to said second end of said second blade. 

1. A cutting mechanism comprising: a. a frame member; b. a first blade mounted to said frame member; c. a second blade; and d. means for coupling said second blade to said frame member at a predetermined cutting angle relative to said first blade and foR allowing said second blade to be laterally movable relative to said first blade while maintaining said predetermined angle strip springs said first and second blades and including, a pair of strip springs each having first and second ends at first and second ends of its length, means for rigidly mounting said first ends to said frame member, means for rigidly securing said second ends together to allow a lateral flexing movement of said second ends while preventing twisting movements thereof, and means for mounting said second blade to said securing means to position said second blade such that its length extends in substantially the same direction as the lengths of said pair of strip springs and to provide for a cutting movement of said second blade relative to said first blade during said lateral flexing movement while said first and second blades are maintained at said predetermined cutting angle due to the prevention of twisting movements of said second ends.
 2. Apparatus as set forth in claim 1 wherein said means for mounting said first ends to said frame member include means for mounting said first ends a predetermined distance apart, and said securing means includes means for securing said second ends together at said predetermined distance apart, whereby said springs are parallel to each other.
 3. Apparatus as set forth in claim 2 wherein said means for mounting said second blade to said securing means includes a third spring for pressing said first and second blades together.
 4. Apparatus as set forth in claim 3 wherein said third spring includes a third strip spring.
 5. Apparatus as set forth in claim 4 wherein: a. said second blade has first and second ends; b. roller means are provided adjacent to said first end of said second blade for pressing said second blade against said first blade; and c. said means for mounting said second blade to said securing means includes means for fastening said third strip spring adjacent to said second end of said second blade.
 6. Apparatus as set forth in claim 5 and further including a prime mover means for laterally moving said securing means, whereby the cutting mechanism is actuated.
 7. Apparatus as set forth in claim 1 wherein said means for mounting said second blade to said securing means includes a third spring for pressing said first and second blades together.
 8. Apparatus as set forth in claim 7 wherein said third spring includes a third strip spring.
 9. Apparatus as set forth in claim 8 wherein: a. said second blade has first and second ends; b. roller means are provided adjacent to said first end of said second blade for pressing said second blade against said first blade; and c. said means for mounting said second blade to said securing means includes means for fastening said third strip spring adjacent to said second end of said second blade. 